The Limnology Program encompasses two important monitoring projects, Lake Surveys and Aquatic Rearing Monitoring (ARM), which aid in evaluating juvenile salmon rearing conditions on Kodiak and Afognak Islands. Lake survey sampling collects information including water quality, nutrients, and zooplankton information which help assess rearing conditions and is used in stocking recommendations and exploratory rehabilitation projects. ARM sampling concentrates on specific net-pen rearing sites where Pillar Creek and Kitoi Bay hatcheries raise sockeye and coho juveniles before being released as age-1 smolt into strategically planned sites.
Samples collected during lake surveys include zooplankton net hauls, water samples, temperature and dissolved oxygen profiles, and light incidence measurements. In the laboratory, zooplankton is measured and enumerated under the microscope and water samples can be analyzed for pH, alkalinity, chlorophyll a, and nutrient content.
ADF&G uses limnology data to assess lake productivity and changes in the freshwater rearing environment of sockeye salmon. From these analyses, ADF&G provides stocking recommendations to KRAA for sockeye salmon projects.
Limnology data collected on sockeye salmon nursery lakes that are not regularly stocked with salmon are archived to provide baseline information. The data is important in instances where sockeye returns begin to dwindle. The baseline limnology and zooplankton data can be used to attribute, or rule out, run failures caused by unfavorable juvenile rearing conditions.